Barrett M99 50.BMG single shot rifle.
I've noticed that many people like single shot rifles, so here's one.
To shoot:
1. Open the bolt (move the bolt handle up and to the left)
2. Put a cartridge into the rifle's receiver.
3. Close and lock the bolt (move the bolt to the right and down)
4. Turn the safety off
5. Pull the trigger (or press [return] key to fire)
6. Operate the bolt to eject spent case (ejector works fine, so don't do it by dragging spent case out).
Weapon shouldn't break easily, but be gentle for it anyway.
Bolt likes to unlock itself while shooting, sometimes it even explodes, so also be patient.
Have phun.
